TestSens (Impedance Tube)

Material Sound Transmission Loss and Acoustic Impedance Tube Systems

TestSens acoustic performance measurement system is an acoustic impedance, sound transmission loss and sound absorption coefficient measurement system operating in accordance with ASTM E-2611, ASTM E-1050, ISO 10534-2 standards. Measurements can be made at a frequency of 50Hz - 6400 Hz, under room conditions, temperature and pressure. There are 2 different diameter tubes (100mm, 29mm diameter) for low and high frequency measurements.


  • Detection of sound transmission properties (sound transmission loss, characteristic impedances, characteristic wave number)
  • Determination of sound absorption properties (sound absorption coefficient, complexity coefficient, surface impedance)
  • Dynamic density and dynamic volume modulus detection
  • Detection of transfer matrix elements
  • Random direction (random incidence) noise absorption coefficient estimation models
  • Tube damping correction algorithm for very low damping materials
  • Conical adapter correction algorithm for sound transmission measurements
  • Determination of material micro properties with Johnson-Champoux-Allard-Lafarge (JCAL) material model. (Porosity, Flow Resistance, Stiffness, Viscous Character Length, Thermal Characteristic Length, Static Thermal Efficiency)
  • Amplitude and phase calibration for microphones
  • Switchable frequency resolution and average number

System features

  • ASTM E2611 (4 Pole Transfer Matrix Method) measurement method
  • ASTM E1050 and ISO 10534-2 (Transfer Function Method) measurement method
  • 50 - 6400 Hz data transmission loss and sound absorption coefficient measurement
  • Specially designed phase-compatible microphones
  • Construction manufactured with high surface tolerance
  • Acoustically sealed structure

System Components

  • Measuring tubes with 100 mm and 30 mm inner diameter
  • Dynamic signal analyzer
  • GRAS phase-matched measuring microphones
  • GRAS sound calibrator
  • 25W audio power amplifier

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